1. Field of the Invention
The present invention relates to a new type of solid bath preparation for cosmetic, hygienic and therapeutic use, which has both the properties of a solid bath salt and those of liquid products, and is especially characterized by the addition of lipid components, vesicle forming lipids, tensides and in some cases mineral salts. They may also contain active components, adjuvants such as stabilizers, adsorbing substances, lubricants, and slippage and breakdown promoting agents.
The invention furthermore relates to the preparation of such products and their use.
2. Description of the Related Art
Heretofore bath products have been mostly liquid preparations in the form of tenside solutions with the addition of essential oils and other active components, gels, especially for shower bathing, or in the form of dissolved salts. Among the liquid preparations, those tenside products which contain a proportion --possibly a very high proportion--of oils and other fat-like products, are in a class by themselves.
A special advantage of these bath oils is to be found in the fact that they contain vesicle forming lipids as additives and are capable of the spontaneous formation of liposomes (German Patent 42 05 548).
In these liquid preparations, no O/W tensides are normally contained, since they may prevent spontaneous vesicle formation. Only under certain conditions is it possible to make bath preparations with a lipid content and OW tensides with vesicle forming properties. This is shown in German Offenlegungsschrift 196 02 346.7-41. According to the latter, preparations with a content of more than 30% of lipophilic components and vesicle forming substances can have spontaneous vesicle formation only if a complexation of the O/W tenside is performed with W/O tensides. The molar ratio of W/O to O/W tensides amounts to 1:2 to 1:0.2.
The above-named bath oils are either liquid or semi-liquid, spreadable preparations. However, they contain no electrolytes since the latter might undesirably influence the consistency of the composition. Furthermore, special measures must be taken with regard to the transport and dosing of such products.
Solid bath products, namely bath tablets, which are characterized by the release of CO.sub.2 into the bath water due to their effervescent character, are easier to handle from the packaging and transport point of view --especially in the case of glass bottles (injury hazard), and can also contain electrolytes. They are composed of an effervescent combination of carbonate or bicarbonate and an acid, preferably citric or tartaric acid, binders (cellulose derivatives or starch), bursting agents and lubricants (talc, Macrogol (polyethylene glycol), and essential oil additives, perfumes, dyes and tensides.
Carbonic acid not only gives the bath a pleasantly tingling feeling but also has a dilating effect on the blood vessels in the skin, promoting circulation and having a regulating effect on the heat and cold receptors of the skin, i.e., on the organs of touch which convey the feeling of warmth and cold.
Such effervescent bath salts tablets are described in G. A. Nowak, "Die kosmetischen Praparate,"2nd ed., 1975, pp. 672-674 and cover, for example, compositions of sodium carbonate, tartaric acid, talc, sodium hexametaphosphate, potato starch, carboxymethylcellulose, pectin, sodium lauryl sulfate, dyes and perfume oil.
In K. H. Schrader, "Grundlagen und Rezepturen der Kosmetika," 2nd ed. 1989, p. 606, a noneffervescent bath salt of sodium chloride and sodium sulfate is described, and on page 390 of the 1979 edition, effervescent bath tablets of sodium hydrogen carbonate, tartaric and boric acid, wheat starch powder, kaolin, perfume and apple pectin.
As it can be seen from this, bath tablets--especially effervescent bath tablets--contain no tenside-lipid combination with a skin-cleaning and skin-care action.
If it is desired to apply the knowledge obtained from liquid bath preparations regarding the tenside-lipid combination to solid products such as effervescent bath tablets, it will be impossible, since compressed tablets can contain only extremely small amounts of liquid and fats if they are to remain stable.
The addition of liquid or paste lipids and tensides adversely affects the flow and tableting and the galenically relevant properties of the tablets with regard to friability, strength and solubility and makes the production of individually measured solid (medicated) tablets impossible.